1. Field of the Invention
The present invention relates to an evaporated fuel treatment apparatus which has a canister for adsorbing an evaporated fuel produced in a fuel tank and which treats the evaporated fuel.
2. Description of the Related Art
Conventional evaporated fuel treatment apparatuses cause a canister to adsorb an evaporated fuel, thereby preventing the evaporated fuel produced in the fuel tank from being released to the atmosphere at the time of fuel charging. Thus, a pressure of the fuel tank is reduced (see, for example, JP 2001-140705A).
According to the conventional evaporated fuel treatment apparatuses, the control valve is provided at a vapor path between the fuel tank and the canister, the control valve is opened prior to fuel charging in order to allow the canister to adsorb the evaporated fuel in the fuel tank through the control valve, thereby reducing the pressure inside the fuel tank. Reduction of the pressure prevents the evaporated fuel from being released to the atmosphere during fueling.
According to the conventional evaporated fuel treatment apparatuses, the canister becomes able to adsorb the evaporated fuel upon opening of the control valve. As the control valve a control valve capable of changing a flow rate therethrough by a duty control has been used.